Autoimmune diseases, e.g., multiple sclerosis (MS), insulin-dependent diabetes mellitus (IDDM), systemic lupus erythernatosus (SLE), rheumatoid arthritis (RA), inflammatory bowel disease (IBD) and psoriasis represent assaults by the body's immune system which may be systemic in nature, or else directed at individual organs in the body. They appear to be diseases in which the immune system makes mistakes and, instead of mediating protective functions, becomes the aggressor (1).
MS is the most common acquired neurologic disease of young adults in western Europe and North America. It accounts for more disability and financial loss, both in lost income and in medical care, than any other neurologic disease of this age group. There are approximately 250.000 cases of MS in the United States.
Although the cause of MS is unknown, advances in brain imaging, immunology, and molecular biology have increased researchers' understanding of this disease. Several therapies are currently being used to treat MS, but no single treatment has demonstrated dramatic treatment efficacy. Current treatment of MS falls into three categories: treatment of acute exacerbations; modulation of progressive disease, and therapy for specific symptoms. MS affects the central nervous system and involves a demyelination process, i.e., the myelin sheaths are lost whereas the axons are preserved. Myelin provides the isolating material that enables rapid nerve impulse conduction. Evidently, in demyelination, this property is lost. Although the pathogenic mechanisms responsible for MS are not understood, several lines of evidence indicate that demyelination has an immunopathologic basis. The pathologic lesions, the plaques, are characterised by infiltration of immunologically active cells such as macrophages and activated T cells (2).
In WO 92/18483 quinoline derivatives substituted with a R.sub.A S (O).sub.n -group (R.sub.A =lower alkyl or aryl; n=0-2) are claimed, stated to possess an inunulomodulating, anti-inflammatory and anti-cancer effect, However, said substituents are only disclosed in the 6-position of the quinoline ring.
Further, in U.S. Pat. No. 4,547,511 and in U.S. Pat. No. 4,738,971 and in EP 59,698 some derivatives of N-aryl-1,2-dihydro-4-substituted-1-alkyl-2-oxo-quinoline-3-carboxamide are claimed as enhancers of cell-mediated immunity. The compound ##STR2## known as roquinimex (Merck Index 12th Ed., No. 8418) belongs to this series of compounds. Roquinimex has been reported to have multiple immunomodulatory activities not accompanied with general immunosuppression.
Furthermore, in U.S. Pat. No. 5,580,882, U.S. Pat. No. 5,594,005, WO 95/24195 and WO95/24196 quinoline-3-carboxamide derivatives are claimed to be useful in the treatment of conditions associated with MS, type I diabetes, inflammatory bowel disease and psoriasis, respectively. The particular preferred compound is roquinimex.
The substitution, i.e, type and pattern, of the above compounds, specifically mentioned in the prior art, places them outside the scope of the present invention.
In clinical trials comparing roquinimex to placebo, roquinimex was reported to hold promise in the treatment of conditions associated with MS (3, 4). There are, however, some serious drawbacks connected to some quinoline-3-carboxamide derivatives. For example, it has been found that roquinimex is teratogenic in the rat, and induces dose-limiting side effects in man, e.g., a flu-like syndrome, which prevents from using the full clinical potential of the compound.